Manual hoist and traction machine

Abstract

A manual hoist and traction machine wherein an outer diameter of a first lining plate constituting a mechanical brake is made smaller than an inner diameter of a driven disc of a handwheel. The outer diameter of a second lining plate and of a driven disc are made smaller than an inner diameter of a cylindrical portion of a braking ratchet wheel, and the first and second lining plates are formed of a lining raw material having improved performance with a compressive strength of 15 (Kgf/mm 2 ) or more and a maximum strain of 12 (10 -3 mm/mm) or more.

What is claimed is: 
     
       1. A manual hoist and traction machine comprising: first and second side plates;   a load sheave supported between said first and second side plates by first and second bearings;   a driving shaft for driving said load sheave;   a driven member coupled with said driving shaft and having a friction surface;   a driving member threadedly mounted to said driving shaft and having a friction surface opposite to the friction surface of said driven member; and   a mechanical brake provided between said driven member and said driving member and comprising a braking ratchet wheel having friction surfaces at both axial sides; a braking pawl engageable with said braking ratchet wheel at an outer periphery thereof; first and second lining plates interposed between the friction surfaces of said driven member and braking ratchet wheel and between the friction surfaces of said braking ratchet wheel and driving member, respectively, wherein said lining plates comprise heat resistant fiber, a friction regulating agent and bonding agent which are mixed in the following ratio: heat resistant fiber: 28 to 35 (V %)   friction regulating agent: 20 to 37 (V %)   bonding agent: 35 to 45 (V %)     and have the following resulting characteristics: hardness (HRS): 90 to 120   bending strength (Kgf/mm 2 ): 9 to 15   maximum strain (10 -3  mm/mm): 12 to 16   compressive strength (Kgf/mm 2 ): 15 to 20   coefficient of friction (200° C.): 0.25 to 0.60.     
     
     
       2. A hoist and traction machine according to claim 1, wherein said driving member comprises a handwheel provided with a wheel and boss threadedly mounted to said driving shaft and a hand chain engageable with said wheel of said handwheel, a side surface of said boss at the mechanical brake side having a friction surface, said wheel having a minimum number of pockets for receiving therein horizontal links of said hand chain and said wheel having an inside extending portion extending inwardly from said boss so as to be displaced toward said first side plate with respect to said friction surface at said boss, said hoist and traction machine being so assembled that: an outer diameter of said first lining plate is smaller than an inner diameter of said inside extending portion at said wheel;   said braking ratchet wheel being provided with a cylindrical portion extending from the outer periphery of said ratchet wheel toward said side plate, the outer periphery of said cylindrical portion being provided with teeth with which said braking pawl comes into contact, said teeth being displaced toward said first side plate with respect to said inside extending portion of said wheel, and outer diameters of said second lining plate and driven member being provided with said friction surface which are smaller than an inner diameter of said cylindrical portion at said braking ratchet wheel.   
     
     
       3. A manual hoist and traction machine according to claim 2, wherein said cylindrical portion of said braking ratchet wheel is partly extended inwardly beyond an outer periphery of said first bearing by which said load sheave is supported to said first side plate. 
     
     
       4. A manual hoist and traction machine according to claim 2, wherein the friction surfaces on at least said driven member and braking ratchet wheel with which said first and second lining plates are axially biased by forward screw movement of said handwheel so as to come into frictional contact are provided with friction control layers comprising plated layers, said plated layers being heat-treated. 
     
     
       5. A manual hoist and traction machine according to claim 1, wherein said driving member comprises a brake holder screwably mounted to said driving shaft and having a cylindrical portion and a flange having at the inside-thereof a friction surface, a handwheel having a boss having at both axial sides thereof friction surfaces and an inside extending portion and rotatably supported to said cylindrical portion of said brake holder, and a hand chain engageable with said handwheel, to said cylindrical portion at said brake holder is screwably mounted a load setting and adjusting member, a first friction plate is interposed between said flange of said brake holder and said boss of said handwheel, a second friction plate is interposed between said boss and said load setting and adjusting member, and a holding plate and an elastic member are interposed between said second friction plate and said load setting and adjusting member, thereby forming an overload prevention device, and outer diameters of said flange at said brake holder and first and second friction plates are made smaller than an inner diameter of said inside extending portion at said handwheel. 
     
     
       6. A manual hoist and traction machine according to claim 5, wherein the outer diameter of said elastic member, holding plate and load setting and adjusting member at said overload prevention device are made smaller than the inner diameter of said extending portion at the an axially outside surface, and said overload prevention device is contained within the plane of projection of both said axial surfaces at said wheel of said handwheel. 
     
     
       7. A manual hoist and traction machine according to claim 5, said friction surfaces of at least said flange of said brake holder and holding plate among said friction surfaces with which said first and second friction plate come into frictional contact are provided with friction control layers comprising heat-treated plated layers. 
     
     
       8. A manual hoist and traction machine according to claim 1, wherein said driving member comprises a brake holder having a cylindrical portion and screwably mounted to said driving shaft and having a cylindrical portion and a flange having at the inside surface a friction surface, a driving gear which has a boss having at both axial sides friction surfaces, and teeth positioned at the outer periphery; and an operating lever having a driving pawl engageable with said teeth at said driving gear, to said cylindrical portion of said brake holder is screwably mounted a load setting and adjusting member, between said flange of said brake holder and the boss of said driving gear is interposed a first friction plate, between said boss of said driving gear and said load setting and adjusting member is interposed a second friction plate, and between said second friction plate and said load setting and adjusting member are interposed a holding plate having a friction surface and an elastic member to thereby form an overload prevention device, and at the friction plates of said flange at said brake holder, driving gear, and holding plate, are each provided with a friction control layer formed of a plated layer which is heat-treated. 
     
     
       9. A manual hoist and traction machine according to claim 8, wherein said friction control layer each are formed of nickel phosphate, nickel chromium, or chromium. 
     
     
       10. A manual hoist and traction machine according to claim 8, wherein the heat treatment temperature of said plated layer is set to an austenite transformation point temperature of raw material of each of said brake holder, driving gear and holding plate, and said plated layer is diffused onto the surface of said each raw material.